1. Field of the Invention
This invention relates to cycloidal fluid flow engines, which have their mainshaft transverse to the external flow, their blades move on a quasi cylindrical orbit around the mainshaft, but with respect to the external flow, the blades follow a path which closely approximates a cycloid or a trochoid. Therefore pitching oscillations of the blades must be maintained continuously. During steady operation, the pitch cycles repeat with each orbit of the blades. Control of the engine output is accomplished by cyclic change of the pitch of each blade. Cycloidal fluid flow engines convert the energy of fluid flow into shaft power and vice versa and are used as turbines and propellers.
2. Description of the Prior Art.
Prior art uses eccentric, cam and springloaded devices for direct control of the pitch angles in cycloidal turbines and propellers, having highly loaded and wearing components and can produce only the accurate pitch for operation at low advance ratio.
Indirect pitch control of freely rotating blades by means of trim tabs, controlled by cam devices, has been proposed, but is insuficient for achieving accurate pitch control throughout the range of advance ratios because a trimtab alone can not provide for the longitudinal stability and control needed for accomplishing the fast pitch changes by a cycloidal turbine even at very low speeds. Furthermore propeller operation is not possible.
Prior art has not employed adequate systems for compensation of inertia interaction effective in indirectly pitch controlled systems, therefore cycloidal engines of high efficiency have not been accomplished.